1. Field of the Invention
The present invention relates to a device for energizing, using an inverter, a motor contained in a hermetic box which contains the motor and self reset type protecting device which interrupts the supply of electric power to the motor in case of an abnormal condition.
2. Description of the Prior Art
A compressor for air conditioning has been designed to be capable of finely adjusting the temperature yet contributing to saving energy. For this purpose, therefore, it is accepted practice to energize the motor for driving the compressor using a frequency-variable inverter.
The U.L. Standards state that the motor for driving the compressor be contained in a hermetic box filled with a cooling medium together with self reset type protecting device which interrupts the supply of electric power to the motor in case the motor is abnormally heated or is just going to be heated abnormally.
A known device for energizing a hermetic motor has been disclosed in Japanese Patent Laid-Open No. 46150/1978. A method has also been known to apply to the electric motor an electric power starting from a low frequency and a small output to suppress the starting current at the time of re-starting the inverter.